CONSTRUCTION EQUIPMENT INCLUDES ELECTROPNEUMATIC IMPACT MECHANISMS

Abstract

The invention relates to a construction apparatus comprising an electro-pneumatic impact mechanism, differing only in that it comprises an air-spring type impact mechanism having at least one vent as well as a compressor, wherein the compressor is connected to at least one vent of the impact mechanism and is capable of compressing ambient air and supplying this air to the impact mechanism by compressed air, wherein it is better if the construction apparatus comprises an air filter connected in series with the compressor so that the compressor can supply filtered compressed air to the impact mechanism, and wherein it is better if the construction apparatus comprises at least a first pressure reducing valve capable of reducing the pressure p1 of the compressed air produced by the compressor to a specific value p2 before this compressed air is supplied to the impact mechanism. It is better if the compressor and / or the first pressure reducing valve are of a controllable nature.

Description

[0001] Working device with electro-pneumatic impact mechanism

[0002] Technical area

[0003] The invention relates to tools with electropneumatic impact mechanisms. This includes tools with electrically driven pneumatic spring impact mechanisms.

[0004] background

[0005] Electro-pneumatic impact mechanisms generally use an electric motor to drive a first piston to perform an axial reciprocating movement, the first piston in turn driving a second piston, the so-called flying piston, by means of an air spring, which consequently also performs a reciprocating movement.

[0006] The flying piston is thereby stimulated to periodically strike a striker or the end face of a tool. The air spring between the flying piston and the first piston protects the drive, comprising the electric motor and, if applicable, the gearbox, from mechanical repercussions, particularly hard blows. The flying piston thus strikes the end face of a tool like a hammer, either directly or with the aid of an intermediate striker. These blows enable, for example, effective drilling or chiseling in hard materials with high energy input and consistent impact force.

[0007] Such devices are generally known in the art, for example, as demolition hammers, chisel hammers, and drill hammers. The disadvantages and limitations of such devices are also generally known. Summary of the invention

[0008] Technical problem

[0009] In this case, the inventive problem consists in a general improvement of working tools with electropneumatic impact mechanisms. At least their

[0010] Power-to-weight ratio is improved, and / or their efficiency is increased, and / or the pressure peaks occurring in their air spring impact mechanisms are reduced.

[0011] Furthermore, the user should preferably be effectively protected from harmful hand-arm vibrations caused by the impact mechanism. Furthermore, the tool should preferably be protected from the ingress of dust; in particular, the actual impact mechanism should be protected from dust contamination.

[0012] Solution

[0013] This object is achieved by a working device with an electropneumatic impact mechanism according to one of claims 1-18. A working device according to the present disclosure is, for example, a working device with an electrically driven pneumatic spring impact mechanism, for example a demolition hammer, chisel hammer, or hammer drill.

[0014] Description of the characters

[0015] Figure 1 shows schematically an exemplary structure of a percussion assembly according to the invention.

[0016] Fig. 2 shows an exemplary structure of an alternative linear drive (instead of a rotating machine as in Fig. 1) for an impact mechanism assembly according to the invention. Fig. 3 shows a schematic and partial view of an impact mechanism as can be advantageously used in the work tools according to the invention.

[0017] Fig. 4 shows schematically an exemplary structure of a working device according to the invention, for example a demolition or chisel hammer, with electro-pneumatic impact mechanism.

[0018] Detailed description

[0019] The inventive problem is solved by charging the percussion mechanism by means of a compressor, i.e. the amount of air contained in the percussion mechanism and thus the so-called filling level is increased.

[0020] In a device according to the invention, the drive is preferably provided directly by an electric machine, which is designed, for example, as a linear drive or a rotating machine. The direct drive eliminates the (reduction) gear required in conventional devices. The weight of the gear, as well as the weight of the gear housing and the lubricants, is saved. This also saves installation space. Without a gear, there are also no gear losses, which in conventional arrangements can easily account for 20% of the drive power.

[0021] A device according to the invention can be built without an external power supply, as the energy supply is provided by rechargeable batteries. The weight and space savings allow the use of more rechargeable batteries while maintaining the same overall device weight. This can increase the operating time of a battery-powered device or increase the instantaneous power. For a given electrical output, increasing the size of the rechargeable batteries results in lower ohmic losses at the internal resistance of the batteries during operation, thus improving the overall efficiency.

[0022] Working devices according to the invention preferably comprise both an electrically driven pneumatic spring impact mechanism and a compressor, wherein the pneumatic spring impact mechanism has at least one air intake opening. The compressor draws in ambient air, compresses it, and can feed the pneumatic spring impact mechanism via its air intake opening(s). The pneumatic spring impact mechanism can therefore be supplied with compressed air. Preferably, at least one air filter is provided to filter the air drawn in by the compressor before and / or after compression, so that it can be assumed to be essentially dust-free.

[0023] This means that the air spring impact mechanism can be operated with a much higher filling level compared to the state of the art.

[0024] The invention initially appears remote in several respects:

[0025] 1) The power-to-weight ratio should be improved, i.e., reduced. However, a compressor represents an additional component and therefore an additional weight.

[0026] 2 ) The heat losses of compressors are well known .

[0027] By compressing working gases, compressors not only increase their pressure but also their internal energy - and thus the temperature, whereby usually even in frictionless fall a predominant part of the

[0028] Compression work appears as waste heat. Compressed air-driven machines are therefore known for their low overall efficiency. 3) Increasing the pressure and filling level of the pneumatic spring impact mechanism also seems to be a remote means of reducing pressure peaks.

[0029] Regarding (1): The invention can be understood based on known tools with electropneumatic percussion mechanisms. A consideration of such a percussion mechanism yields the following, as a first approximation:

[0030] An increase in the filling level by a factor of N with N > 1 can, if the mass of the flying piston is also increased by a factor of N, lead to identical pressure conditions in the air springs and to an N-fold higher impact energy at the same impact frequency (assuming that N-fold average mechanical power is supplied to the impact mechanism during operation).

[0031] However, if the mass of the flying piston is not increased or is increased by less than the factor N when the filling level is increased by the factor N, lower compression ratios and correspondingly lower pressure ratios can be achieved in the impact mechanism, which leads to correspondingly lower heat losses.

[0032] It is also possible, for example, to reduce the cross-section of the impact mechanism by a factor of N when the filling level is increased by a factor of N with N > 1. If the mass of the flying piston remains unchanged, for example because its length is increased by a factor of N, the pressure conditions in the impact mechanism do not have to change. The impact energy does not necessarily change either. However, the impact mechanism can have a cross-section of have a reduced inner diameter.

[0033] One of the effects of the invention is to enable the use of long flying pistons. Long flying pistons are understood in the narrower sense to mean those for whose length L the following applies: L > APmax / (p * 9 . 81Nkg -1 ) , where p is the mean density of the flying piston , and APmax is the ( during operation ) maximum pressure difference felt by the flying piston during suction of the flying piston by the excitation piston .

[0034] In a broader sense, flying lobes are to be considered long if their length is at least twice their diameter.

[0035] The use of long flying sticks has several advantages:

[0036] A long (“slim”) flying piston can produce a more favorable impact shape on the die or in the tool, characterized by a longer lasting compression wave, followed by a steeper transition to a decompression wave, whereby - with the same impact energy - the demolition performance can be increased.

[0037] In addition, a long flying piston makes it easier to achieve the required sealing without contact, particularly by means of gas-dynamic seals, for example like the gas-dynamic seals in labyrinth axial piston compressors. The simple (single-stage) mechanical seals that have been used up to now are inevitably subject to wear, which can escalate if their so-called pv values ​​are exceeded. (The pv value is the product of the pressure p to be sealed and the displacement speed v.) Non-contact seals are almost wear-free and have no pv values ​​that could be exceeded. Non-contact seals also enable such impact mechanisms to operate at higher flying piston speeds, which can allow lighter flying pistons to be used for the same impact energy and consequently reduce recoil.When designing flying pistons in percussion mechanisms, their elastic deformation during impact (against the striker) must be taken into account. This dynamic deformation must under no circumstances lead to jamming of the flying piston in the cylinder (or the excitation piston designed as a cylinder).

[0038] Regarding (2): During operation of the percussion mechanism, almost no compressor power is required, which is why the intrinsically low efficiency of compressors is irrelevant in this case. At most, the frictional power of the compressor must be taken into account. The compressed air available from the compressor, which is preferably filtered, enables further improvements:

[0039] For example, compressed air can be used as sealing air to prevent dust-laden ambient air from entering the impact mechanism and thus preventing its contamination with dust. Compressed air can also be used to drive a play compensation device between the tool and the substrate: By continuously pressing the tool against the substrate via the anvil using compressed air, firm contact between the tool and the substrate can be ensured during impact of the flying piston (against the anvil), even at high impact frequencies. Furthermore, pneumatic or electro-pneumatic vibration isolation can be supplied with compressed air.

[0040] Impact mechanisms charged according to the invention offer further advantages. For example, after impacting the flying piston, more pneumatic energy is available to reset the flying piston (in the direction of the excitation piston).

[0041] Regarding ( 3 ): The operation with a charged gas spring leads in an adiabatic approximation at deflection x of the gas spring up to a certain counterforce F(x) , corresponding to a certain pressure p_x, to a smaller difference to the initial pressure p_0 in the forceless F(x=0)=0 neutral position of the gas spring: F (x) = A* (p_0* (V_0 / V_x) A gamma-p_0 ) . The quotient p_0 / p_x therefore increases with increasing p_0, and the temperature increase in the compressed gas associated with the deflection of the gas spring is correspondingly lower, thereby reducing wall losses (heat loss and thus energy loss and efficiency reduction).

[0042] The invention is described below with reference to several embodiments which are in no way to be understood as limiting but are only intended to facilitate the implementation of the invention.

[0043] In the examples, the exciter piston of a percussion mechanism is driven directly or indirectly by a linear or rotary electric motor. The same electric motor can drive a compressor or act as one itself. The compressed air thus available can, among other things, influence (charge) the pneumatic spring percussion mechanism.

[0044] The embodiment from Fig. 1 shows schematically a possible structure of an impact mechanism assembly according to the invention, comprising an (air spring) impact mechanism 100 for driving in a tool, an electric motor 110, a compressor 120, two air filters 131 and 132, two reducing valves 141 and 142, an optional heat exchanger 150, and a fan for cooling the motor 160. Both the compressor 120 and the reducing valves 141, 142 can be designed to be controllable. The first air filter 131 can be larger and coarser than the smaller and finer second air filter 132. A rotating electrical machine or according to the invention. Electric motor 110 preferably has a low base speed range (e.g. a lower base speed range than conventional radial flux synchronous machines of the same power), otherwise one or more gear stages can be provided between motor 110 and impact mechanism 100.Axial flux machines, particularly those without a yoke (so-called "YASA motors"), can have a suitable speed range and a good power-to-weight ratio. Expertly dimensioned Vernier machines designed as radial flux machines, particularly permanently excited ones, and among these also external rotor machines, are also suitable for implementing the invention. Transverse flux machines and synchronous machines with radial flux guidance and double rotor are also suitable.

[0045] If the motor 110 is a rotating machine, it is preferably mechanically connected to the exciter piston via a crank or wobble drive in order to convert the rotational movement of the motor into a linear oscillation of the exciter piston.

[0046] A compressor 120 is also driven via the output shaft of the machine or electric motor 110. Eccentric pumps, particularly rotary vane pumps, that can be mounted directly on the shaft are particularly suitable for this purpose. Greater integration of the assembly can be achieved by combining functionally identical components of the assembly, for example, by having the motor housing also serve as the pump housing. The air filters 131 and 132 can be used to remove dust from the outside air before it is fed to the compressor or impact mechanism.

[0047] With the valves 141 and 142, the pressure of the generated compressed air can be reduced to a certain extent or to a predetermined level before it is fed into the compartments of the pneumatic spring impact mechanism 100 or is also diverted as sealing air. Depending on the compression ratio and the thermal coupling of the line network with the environment, a heat exchanger 150 may be necessary to cool the compressed air. A fan 160, which serves to cool the motor with uncompressed ambient air filtered by the air filter 131 ("cooling air"), is preferably also mounted on the motor shaft. The motor 110 can be designed to be directly air-cooled, or, for example, a heat exchanger (not shown) of a liquid cooling system of the motor 110 is supplied with the cooling air. By appropriately directing this cooling air, it is also possible to form an air curtain to limit / direct the dust when processing the surface, e.g.to protect the user from this dust pollution.

[0048] Using a linear drive as in the exemplary embodiment in Fig. 2 instead of a rotating machine as in Fig. 1 eliminates the need for a crank or wobble drive. In a device according to the invention, a linear-acting machine can be advantageously combined with a double-acting gas spring. This is tensioned by approaching the drive piston of the linear machine to one of its end positions, which are also the reversal points of the linear movement, whereby the drive piston is initially braked and then accelerated in the opposite direction. This brings about the necessary reversal of movement in a mechanically advantageous manner without any “hard shocks” and at the same time gives the drive piston a high initial acceleration in the opposite direction, which increases the electrical efficiency of the linear drive. Also advantageous for the efficiency of the linear machine is current supply only at high drive piston speeds, i.e.at a drive piston speed that is above a predetermined threshold value .

[0049] Fig. 2 contains the linear motor 210, which in turn consists of stator 211 and the rotor with permanent magnets 212, which on the one hand drives the excitation piston of the striking mechanism (left outside of Fig. 2) or is designed as such, wherein the rotor on the other hand is designed as a (drive) piston 213 or is mechanically connected to such a piston directly or indirectly (e.g. via an incompressible fluid), which divides the volume 220 into the two variable partial volumes 221 and 222. The partial volumes 221 and 222 form, with piston 213, a gas or air spring with a double-acting piston 213.

[0050] The partial volume 222 is further divided by the connection of the two check valves 231 and 232 into an area acting as a gas or air spring to the right of the valve connections, as well as a working volume between piston 213 and the valve connections.

[0051] The volume 220 thus combines the function of a compressor with that of a double-acting gas spring, which enables the return of the rotor 212 toward a center stroke position. The intermittently conveyed and compressed air can be stored and used in a compressed air reservoir (not shown) for the same purposes as in the previous embodiment, i.e., it can be directed into the compartments of the pneumatic spring impact mechanism 100, which enables faster start-up of the impact mechanism.

[0052] By combining the gas spring with the linear drive 210, end positions of the stroke are defined for the latter, or the rotor is braked when approaching the end positions of the stroke and its direction of movement is reversed. The kinetic energy of the rotor and of the parts connected to it can be recuperated in the process. In functional terms, the gas spring replaces the crank or wobble drive in versions of the invention with a linear motor (in versions of the invention with rotating electric motors), and together with valves it can also serve as the compressor according to the invention. By supporting the back and forth movement of the rotor with the double gas spring or gas spring with a double-acting piston acting in the direction of the middle stroke position, it can be achieved during operation that the speed of the rotor along both directions of movement (i.e.parallel or antiparallel to the direction of impact) is high over a large part of the stroke, whereby the progressive characteristics of gas springs have a beneficial effect. "High" in the sense of the invention means that the rotor speed is at least in an upper range of the basic speed range of the linear motor and / or even already in the field weakening range. According to the invention, during operation the linear motor is supplied with electrical power entirely or predominantly when and only when the rotor has already been reversed by the action of the gas spring and the rotor has a high speed. Electrical power is therefore preferably supplied to the linear motor in an upper range of the basic speed range and / or the field weakening range (of the rotor).Furthermore, operation is highly preferably carried out entirely or predominantly in an upper power range of at least 50% and preferably at least 80% of the rated power of the linear motor; prolonged operation at low currents is to be avoided according to the invention. Furthermore, the rotor is preferably driven electromagnetically in both directions of movement, i.e., both during its movement along the direction of impact and during its movement against the direction of impact.

[0053] Through such ongoing operations:

[0054] Electrical power is supplied wholly or predominantly above a certain minimum rotor speed (ie at high speed); and / or

[0055] The motor is operated entirely or predominantly in a high power range, i.e. supplied with high current; and / or

[0056] If the motor is driven in both directions of movement (i.e. supplied with electrical power), a higher electrical efficiency of the linear machine as well as a higher power density or a favorable power-to-weight ratio can be achieved.

[0057] Fig. 3 shows a schematic and partial view of a percussion mechanism as can be advantageously used in the inventive tool. In particular, Fig. 3 shows the exciter piston 300, cylinder 310, tool (e.g., chisel) 320, anvil 330, annular space between the anvil and tool 340, (long) flying piston 350, mechanical seals 360, non-sealing guide rings 370, stop 380 (e.g., made of polymer), vents of the actual percussion mechanism 391 and 392, vents of the anvil guide 393 and 394, and air supply to the annular space 395.

[0058] During operation, compressed air can be supplied to the impact mechanism between the flying piston 350 and the striker 330, as well as between the flying piston 350 and the excitation piston 300, via the snap openings 392 and 391. These snap openings can be connected to a common volume that can be formed by a housing. According to the invention, the flying piston is preferably long (see above). In contrast to conventional flying pistons of known air spring impact mechanisms, it has, for example, a plurality of "cascaded" mechanical seals instead of a single seal. These "cascaded" seals are pneumatically connected in series. In each case, the contact pressure Ppress (i) with i = 1, 2, ... , n of the n mechanical seals is too low for them to be able to individually seal against the maximum pressure difference APmax (between both sides of the flying piston) occurring during operation. The following therefore applies to all n mechanical seals individually: Ppress (i) < APmax.However, with the inventive dimensioning it also applies that (Ppress (l) + Ppress (2) + ... + Press (n) ) > APmax. In this way the pv values ​​of the mechanical seals are only achieved at correspondingly higher (flying) piston speeds. This makes it possible to design the impact mechanism for higher maximum flying piston speeds (during operation) with smaller flying piston masses, which reduces the kickback and thus the vibrations accordingly. Instead of cascaded mechanical seals, gas dynamic seals similar to those used in labyrinth axial piston compressors can be used for the same purpose (i.e. to enable higher flying piston speeds with acceptable wear).

[0059] Amorphous and partially amorphous alloys are particularly suitable as materials for the flying piston 350 and / or the striker 330, as they have very high elastic limits and very high restitution coefficients. In addition, they may have other favorable properties such as excellent corrosion resistance, abrasion resistance, and formability. Amorphous alloys are known as "metallic glasses," for example, from golf clubs, where the high restitution coefficient is utilized. Particularly suitable for implementing the invention are amorphous or partially amorphous alloys of high density, the density of which is preferably matched to the density of the tool material (usually tool steel).An example of a particularly suitable flying piston and / or anvil material is the partially amorphous iron-based alloy SAM2x5-630 (Nanosteel), which can be processed by spark plasma sintering, whereby heavy metal powder, in particular (crystalline) tungsten powder, can be added to the powder to adjust the density.

[0060] In the exemplary embodiment, a portion of the cylinder, in which the exciter and flying pistons run, can be designed as a striker guide to accommodate the striker. With regard to mechanical properties, tribological properties, and corrosion resistance, hard-chrome-plated, so-called "carbide-free" nanostructured bainitic steels are particularly suitable for the cylinder. These steels can be easily machined, at least before bainiticization, and enable significant lightweight construction, particularly by permitting a thinner-walled design of the cylinder and, if necessary, also the tool holder.

[0061] Preferably, the die guide also has vents 393 and 394. Applying different (air) pressures to both vents allows for adjustment of the required tool contact force. A further opening 395 on the cylinder allows the supply of dust-free compressed air of a known pressure as sealing air, for example, into an annular space 340 between the tool and die. This prevents dust from penetrating the impact mechanism and can thus increase its service life.

[0062] Fig.4 shows schematically a working device according to the invention, namely a demolition or chisel hammer, with electro-pneumatic impact mechanism. In particular, Fig. 4 shows the impact mechanism assembly 410, tool (e.g. chisel) 411, (vibration-insulated) device housing 420, bellows 421, guide elements 422, air filter 430, outlet of sealing air through the gap between the tool and the tool holder 431, lateral outlet of the cooling air 432, spring, in particular air spring, e.g. diaphragm air spring or bellows 441, linear motor, in particular voice coil drive (optional) 442, compartment for electrical and electronic components 450, motor control 451, class D amplifier (optional) 452, acceleration sensor (optional) 453, microprocessor (optional) 454, handles 460 (optional), springs, in particular mechanical springs 461 (optional), dampers, e.g. oil dampers (optional) 462.

[0063] The impact mechanism assembly 410 can be constructed, for example, according to Fig. 1, but filter 131 is not attached to the

[0064] Impact mechanism assembly 410 is not attached to the impact mechanism assembly, but as a filter 430 on the device housing 420. The impact mechanism assembly 410 can, for example, have an air spring impact mechanism (see Fig. 3). The impact mechanism assembly 410 is movably mounted on the device housing 420 with the aid of guide elements 422, which enables the entire impact mechanism assembly 410 to move back. The guide elements also serve as a stop and limit the stroke of the impact mechanism assembly 410 relative to the device housing 420. Because of a seal provided by bellows 421, the compressor (not shown) of the impact mechanism assembly 410 can only suck in air that has been filtered by the air filter 430. Sealing air 431 can escape along the tool. Motor cooling air can be released into the environment from the impact mechanism assembly 410. A spring 441 is preferably arranged between the device housing 420 and the impact mechanism housing 410, via which spring the user can, for example, actuate the impact mechanism and, with it, the tool (e.g.the chisel 411) against the surface to be worked on. This spring is preferably a gas spring, in particular an air spring, wherein the air spring can be designed, for example, as a pneumatic cylinder, or - preferably - as a bellows or diaphragm air spring. The air spring can be supplied with compressed air using the compressor of the impact mechanism group 410, for example, with the help of one or more (control) valves. It can also or instead serve as the compressed air reservoir discussed in Fig. 2, which can be considered both for versions of the invention with a rotating motor and for those with a linear direct drive. The (air) spring already effects vibration isolation between the impact mechanism assembly 410 and the device housing 420. Further, active vibration isolation can be achieved by operating a linear drive 442 mechanically parallel to the spring 441.Highly dynamic direct drives such as moving coil drives are particularly suitable as linear drives for this purpose. The linear drive is preferably used to generate a time-dependent force that largely compensates for the force imparted by the spring 441. The signal required for this can be calculated with the aid of a microprocessor 454 attached to the device housing 420 from the signal of an acceleration sensor 453, which is also attached to the device housing 420, and generated by means of a class-D amplifier 452. Advantageously, the mechanical power of the moving coil drive used for vibration isolation is not wasted but inevitably excites the striking mechanism.Preferably, all electrical and electronic components are arranged on or in one or more compartments 450 of the vibration-isolated device housing, whereby mechanical loads which can reduce the service life of electrical and electronic components can be reduced. This is particularly relevant for battery-operated embodiments of the invention, in which the batteries are very preferably also attached to the vibration-isolated device housing. The handles 460 can be suspended from the device housing via dampers so that they can move perpendicularly to the striking axis (or at least with a vertical component), for example via a combination of mechanical springs 461 and oil dampers 462. Active vibration isolation limited to the handles is less useful.

[0065] For embodiments of the invention as a hammer drill, it is expedient to drive the tool holder separately with the aid of a second motor. In this case, both motors (i.e. the one that drives the impact mechanism and the one that drives the tool holder) are preferably liquid-cooled and share (at least partially) a cooling circuit or cooling system. The tool holder can also be driven directly, or with the aid of a reduction gear. A planetary gear arranged coaxially to the impact axis or the tool is particularly suitable as a reduction gear. In this case, the drive can preferably be via the sun gear and the output via the ring gear, while the planet carrier is abutted, for example, on the housing of the impact mechanism assembly 410.

[0066] The use of a separate second motor to drive the tool holder allows the user of the inventive hammer drills with controllable charging pressure of the impact mechanism to select the impact frequency, the impact energy and the speed independently of one another and thus to adapt them to the respective application.

[0067] If the acceleration sensor 453 measures values ​​that are above a certain limit over a certain period of time, the microprocessor 454 can initiate an emergency shutdown of the work device in order to protect the user (and the device).

Claims

Claims 1. A working device with an electropneumatic percussion mechanism, characterized by comprising a percussion mechanism, preferably an air-spring percussion mechanism, with at least one breather opening and a compressor, wherein the compressor is connected to the at least one breather opening of the percussion mechanism and can compress ambient air and supply it to the percussion mechanism as compressed air.

2. Working device according to claim 1, characterized in that it has at least one first air filter connected in series with the compressor, so that the compressor can supply filtered compressed air to the impact mechanism. 3 . Working equipment according to one or more of the Claims 1 to 2 characterized by having at least one first pressure reducing valve which can reduce a pressure pl of the compressed air delivered by the compressor to a certain value p2 before it is fed to the percussion mechanism, where pO < p2 < pl and where pO is the ambient pressure. 4 . Tool according to claim 3, characterized in that at least one second Assign pressure reducing valve to further reduce the pressure p2 to a value p3 with pO < p3 < p2 < pl . 5 . Working device according to one or more of claims 1 to 4, characterized in that a striker guide has separate openings, which can be subjected to different pressures.

6. Working device according to one or more of claims 1 to 5, characterized in that it has a linear or rotary direct drive.

7. A working device according to claim 6, characterized in that the direct drive of the impact mechanism is effected by means of one or more rotating electrical machines, the rotary movement of which is converted into a linear oscillation of the excitation piston by means of a first mechanism, wherein the excitation piston can also be designed as an excitation cylinder. 8 . Working device according to claim 7, characterized in that the first mechanism is a slider crank mechanism, wherein the Slider crank mechanism also with a Double crankshaft can be designed. 9 . Working device according to claim 7, characterized in that the first mechanism is a wobble drive. 10 . Working device with electro-pneumatic impact mechanism, characterized in that an excitation piston of the impact mechanism, which can also be designed as an excitation cylinder, is directly driven by an electric linear motor, wherein the rotor of the linear motor is connected to a gas spring system or is operated on such a system, which moves the rotor from both of its stroke end positions, which are determined by the gas spring system can be driven in the direction of its stroke center position, so that during operation the gas spring system causes the runner to reverse in the area of both end positions. 11 . Tool according to claim 10, characterized in that the tool has a motor control, and that during operation with the help of the motor control the linear motor is supplied entirely or predominantly with a high electrical power of at least 50% and preferably at least 80% of the nominal power of the linear motor, if the speed of the rotor is in an upper range of the basic speed range of the linear motor and / or even in its field weakening range, and wherein the rotor is electrically driven in both directions of movement.

12. A working device according to claim 10 or 11 and one or more of claims 1 to 6, characterized in that a variable volume of the gas spring system is used as a compressor within the meaning of claim 1 with the aid of at least two valves. 13 . Working device according to claim 1, characterized in that a flying piston of the percussion mechanism is long.

14. Working device according to claim 13, characterized in that a flying piston has a gas-dynamic seal in the manner of the seals of labyrinth axial piston compressors. 15 . Working device according to claim 13, characterized in that the flying piston comprises a plurality of pneumatically connected in series has mechanical seals. 16 . A working device with electro-pneumatic percussion mechanism, characterized in that a flying piston and / or a striker are formed entirely or partially from amorphous or semi-crystalline alloys or are lined with such, wherein preferably densities of the flying piston and / or the striker are matched to the density of a tool, preferably a drill or chisel, of the working device. 17 . Working device with electro-pneumatic impact mechanism characterized by having a cylinder and a tool holder, further characterized in that the cylinder and tool holder consist entirely or predominantly of preferably corrosion-protected, carbide-free, nanostructured bainitic steel. 18 . Working device according to claim 1 and one or more of claims 2 to 17 .

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